went from 24'' monitor to a 32'' (1080P) TV. The size feels 'just right'. If anything, I have my monitor placed at just about the THX recommended viewing distance.
I did the same and love the 32-incher. However, you can't compare a 32" 1080P TV to a 30" 2560x1600 monitor. The latter has double the pixels of the 32" and allows you to sit much closer. I sit about 3.5' from my 32" TV, and I would guess that sitting 2' from a 30" 2560x1600 monitor would be just right.
At 2' from such a large screen, I can understand the OP's concerns, but I think they're unwarranted.
Here are the concerns I would have:
Sitting 2' from a 30" display might be fatiguing
Running games at 2560x1600 will require a lot of gpu power, and running games at the non-native resolution is less than optimal
I bought my TV for gaming, hands-down, and I think it's the perfect size for that. If I wanted a larger screen for the sake of more screen real estate (i.e. higher resolution), then a 30" 2560x1600 monitor would've been a better choice (albeit at double the cost).
OP, you should decide if you just want a larger screen because 24" is too small, or if you want the greater screen real estate of the 2560x1600 resolution. If it's the former, then you'd probably be better served by a 32" 1080P TV.